An experimental model is proposed to study the role of tooth eruption in the vertical development of the growing face and dental occlusion. By intentional tooth ankylosis, which will inhibit the eruption of selective groups of teeth, it should be possible to elucidate the form-function relationships in the developing oral area to determine: 1) whether craniofacial form largely follows oral-pharyngeal function or whether oral-pharyngeal function is largely adaptive, 2) whether tooth eruption plays an active and primary role in vertical facial development or a passive, secondary and compensatory role. An investigation of the dental and skeletal compensations over time that will result from differentially inhibiting eruption of maxillary posterior teeth will allow an analysis of the role of dento-alveolar development in the growth direction and pattern of the lower face, particularly in regard to the rotational component of facial growth. The biochemical control factors involved in these processes will also be investigated. Since orthodontic diagnosis and treatment is currently predicated on certain assumptions and hypotheses regarding these inter-relationships, data from a primate model should enhance our understanding and presumably our clinical treatment of dentofacial deformities resulting from unfavorable vertical growth.